Using bazaar I get this advice :
```
$ bzr clone lp:anki i18n
The command 'bzr clone' has been deprecated in bzr 2.4. Please use 'bzr branch' instead.
$ bzr --version
Bazaar (bzr) 2.8.0dev1
Python interpreter: /usr/bin/python 2.7.13
Python standard library: /usr/lib/python2.7
Platform: Linux-4.9.0-5-amd64-x86_64-with-debian-9.3
bzrlib: /usr/lib/python2.7/dist-packages/bzrlib
```
When studying, the learning count now indicates the number of
learning cards due within the learn ahead limit, instead of the total
number of learning steps required to complete that day.
Also fix the ineffective limit clauses in the learning counts.
To avoid all sorts of problems, we need to ensure cards scheduled with
the V2 scheduler are not studied in older clients. Unfortunately we
can't just bump the file's schema version, as the existing clients will
freely import files created with newer versions. This patch changes
that, so things should be a bit easier in the future.
In the mean time, we need a way to prevent older clients from importing
files created with the V2 scheduler. To do this, we switch to using a
'collection.anki21' file in the archive, and include a dummy collection
.anki2 file.
The code has been tested with both deck and collection packages, but
exporting deck packages w/ scheduling info will remain disabled until
the V2 scheduler has had more testing.
We can't preserve the original queues when in preview mode, as
otherwise the due counts report the remaining steps of cards in
the learning queue, instead of just 1.
Rather than the rather complicated approach of making the learning and
deck list code aware of the current mode we're in, preview mode moves
all cards to the review queue when the filtered deck is built - just as
cards are moved to the new queue in Anki 2.0.x. The reason for the
review queue is that users were frequently confused when cards appeared
as new - hopefully this is slightly less confusing.
